<?php

namespace Kirby\Sane;

use DOMAttr;
use DOMDocumentType;
use DOMElement;
use Kirby\Toolkit\Dom;

/**
 * Base class for Sane handlers with DOM file types
 * @since 3.5.8
 *
 * @package   Kirby Sane
 * @author    Lukas Bestle <lukas@getkirby.com>
 * @link      https://getkirby.com
 * @copyright Bastian Allgeier
 * @license   https://opensource.org/licenses/MIT
 */
class DomHandler extends Handler
{
	/**
	 * List of all MIME types that may
	 * be used in data URIs
	 *
	 * @var array
	 */
	public static $allowedDataUris = [
		'data:image/png',
		'data:image/gif',
		'data:image/jpg',
		'data:image/jpe',
		'data:image/pjp',
		'data:img/png',
		'data:img/gif',
		'data:img/jpg',
		'data:img/jpe',
		'data:img/pjp',
	];

	/**
	 * Allowed hostnames for HTTP(S) URLs
	 *
	 * @var array
	 */
	public static $allowedDomains = [];

	/**
	 * Names of allowed XML processing instructions
	 *
	 * @var array
	 */
	public static $allowedPIs = [];

	/**
	 * The document type (`'HTML'` or `'XML'`)
	 * (to be set in child classes)
	 *
	 * @var string
	 */
	protected static $type = 'XML';

	/**
	 * Sanitizes the given string
	 *
	 * @param string $string
	 * @return string
	 *
	 * @throws \Kirby\Exception\InvalidArgumentException If the file couldn't be parsed
	 */
	public static function sanitize(string $string): string
	{
		$dom = static::parse($string);
		$dom->sanitize(static::options());
		return $dom->toString();
	}

	/**
	 * Validates file contents
	 *
	 * @param string $string
	 * @return void
	 *
	 * @throws \Kirby\Exception\InvalidArgumentException If the file couldn't be parsed
	 * @throws \Kirby\Exception\InvalidArgumentException If the file didn't pass validation
	 */
	public static function validate(string $string): void
	{
		$dom = static::parse($string);
		$errors = $dom->sanitize(static::options());
		if (count($errors) > 0) {
			// there may be multiple errors, we can only throw one of them at a time
			throw $errors[0];
		}
	}

	/**
	 * Custom callback for additional attribute sanitization
	 * @internal
	 *
	 * @param \DOMAttr $attr
	 * @return array Array with exception objects for each modification
	 */
	public static function sanitizeAttr(DOMAttr $attr): array
	{
		// to be extended in child classes
		return [];
	}

	/**
	 * Custom callback for additional element sanitization
	 * @internal
	 *
	 * @param \DOMElement $element
	 * @return array Array with exception objects for each modification
	 */
	public static function sanitizeElement(DOMElement $element): array
	{
		// to be extended in child classes
		return [];
	}

	/**
	 * Custom callback for additional doctype validation
	 * @internal
	 *
	 * @param \DOMDocumentType $doctype
	 * @return void
	 */
	public static function validateDoctype(DOMDocumentType $doctype): void
	{
		// to be extended in child classes
	}

	/**
	 * Returns the sanitization options for the handler
	 * (to be extended in child classes)
	 *
	 * @return array
	 */
	protected static function options(): array
	{
		return [
			'allowedDataUris' => static::$allowedDataUris,
			'allowedDomains'  => static::$allowedDomains,
			'allowedPIs'      => static::$allowedPIs,
			'attrCallback'    => [static::class, 'sanitizeAttr'],
			'doctypeCallback' => [static::class, 'validateDoctype'],
			'elementCallback' => [static::class, 'sanitizeElement'],
		];
	}

	/**
	 * Parses the given string into a `Toolkit\Dom` object
	 *
	 * @param string $string
	 * @return \Kirby\Toolkit\Dom
	 *
	 * @throws \Kirby\Exception\InvalidArgumentException If the file couldn't be parsed
	 */
	protected static function parse(string $string)
	{
		return new Dom($string, static::$type);
	}
}
